# Homework Help: Matrix problem

1. Feb 25, 2010

### losmets90

Given the matrix
A= [a 1 9]
[a -6 3]
[5 -8 a]

find all values of a that makes
a can be _ & _

NEED HELP! IM BEYOND STUCK! I have no idea to even approach this problem! Thanks!

Last edited by a moderator: Apr 24, 2017
2. Feb 25, 2010

### netheril96

I don't understand why you are stuck.
You don't know how to calculate determinants or solve equations?

3. Feb 25, 2010

### losmets90

I don't know how to solve the equation

4. Feb 25, 2010

### netheril96

$$$\left| {\left. {\bf{A}} \right|} \right. = 285 - 48a - 7a^2 = 0$$$
You can't solve that?

5. Feb 25, 2010

### losmets90

oh, now I feel dumb. Thanks for the help!